Thermochemical and Constitutional Properties of Al-Si-Mg-Cu Alloys

该特定项目的总体目标-在整个资助期的初始提案中设定-仍然是旨在确定Al-Si-Mg-Cu系统相关合金的热化学和结构特性的系统研究。通过在这些系统中逐步推进热力学计算，选择关键合金样品进行专门的实验研究。这种结合的Calphad型计算与选定的实验将是决定性的最终Calphad型热力学建模的热化学性质和整个相图的最高精度的一致的描述。提供这些直接确定的材料数据是必不可少的理解技术相关的铝合金凝固定量的总体目标，并减少了固有的模糊性，在凝固模型中，这些属性往往被滥用为拟合parameters.In建议期间的工作将集中在铜硅二元和铝铜硅三元系统和选定的四元数据。与“相图的热力学评价”项目一起，仅根据文献中的数据替换初步热力学描述，旨在将新的实验结果与“热力学数据的从头计算预测”的从头计算能量计算相结合。四元Q相及其相平衡将进行更详细的研究。在第一轮“临界凝固实验”的密切合作下，首次实现了Q作为单相的复杂制备后，四元分解反应和相关的温度，以及作为温度的函数的热容）。为此目的，我们提供了一系列专门为热力学和组成合金性能的高精度实验研究而设计的复杂实验室设备。

The global goal of this particular project- set in the initial proposal for the entire funding period - remains the systematic research aiming at the determination of thermochemical and constitutional properties for pertinent alloys of the Al-Si-Mg-Cu system. Dedicated experimental investigations on key alloy samples, selected by progressively advancing thermodynamic calculations in these systems are employed. This combination of Calphad-type calculations with selected experiments will be decisive for the final Calphad-type thermodynamic modelling with a consistent description of both the thermochemical properties and the entire phase diagram with highest precision. Providing these directly determined materials data is essential to the overall goal of understanding technologically relevant solidification of aluminium alloys quantitatively and reduces the inherent ambiguity in solidification models in which these properties are often misused as fitting parameters.In the proposed period the work will focus on the Cu-Si binary and the Al-Cu-Si ternary system and selected quaternary data. Jointly with the project “Thermodynamic evaluation of phase diagrams", a replacement of the preliminary thermodynamic description, based only on data available in the literature, is aimed at, combining the new experimental results and the ab initio energy calculations from “Ab initio prediction of thermodynamic data”. The quaternary Q phase and its phase equilibria will be investigated in more detail. After the complex preparation of Q as a single phase was achieved for the first time in close cooperation with “Critical solidification experiments” in the first round, the key thermodynamic data (heat of fusion resp. quaternary decomposition reaction and associated temperatures, as well as heat capacity as function of temperature) will be determined. To this purpose a spectrum of sophisticated laboratory equipment, specifically designed for high precision experimental investigation of thermodynamic and constitutional alloy properties is available.